SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c99a7c7de6ee07502ae8a157c5caf3624dfd3e02c0e226867d96b6c4b424db3f' 
  AND token = 'bEC/Nw58grqz9+uZ9BRsxcMhKLKEdbR2NdRPuUctxos=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}